Police believe that 35-year-old Joao Rodrigo Silva Santos was abducted on Monday evening. When his wife opened the door to leave for work the following morning, she found a backpack with her husband's head inside.

According to Brazilian media, Santos' eyes and tongue had been cut out.

Santos played for a number of mostly second-tier Rio de Janeiro football clubs before retiring and opening a health food store.

Police refused to comment on lines of investigation, but media have speculated that it could be related to a break-in at Santos' store this year.

Some newspapers also pointed out that his wife works for the police department in one of the shantytowns that recently came under police control, although she reportedly is a social worker there.

And while World Cup tickets are selling at record rates, experts say the violent protest marches that erupted during the Confederations Cup, combined with headlines about crime and violence, might make fans think twice about bringing their families to Brazil.

Brazilians themselves were horrified by the story, but to a certain degree, they have become accustomed to crime and violence.

In Rio de Janeiro, cars drive through red lights at night. The drivers don't stop for fear of being robbed. Brazilians rarely carry cash, using debit cards even to pay for a cup of espresso. In Sao Paulo, criminal "sweeps" of restaurants and bars are common. An armed gang moves through in a matter of minutes, relieving patrons of all their valuables.

Despite that, murders in the states of Sao Paulo and Rio de Janeiro actually dropped 76% and 44% between 2001 and 2011, according to the Rio-based Brazilian Center for Latin American Studies.

The murder rate in Brazil as a whole has risen 132% over the past 30 years but has dropped since reaching a peak in 2003.